Conventionally, as a technology to produce a submicron size of honeycomb-like structure, photolithography, softlithography (see, Whiteside, et al., Angew. Chem. Int. Ed., 1998, Vol. 37, pages 550-575), etc. have been known. Such a miniaturization process for production by finely cutting a material is called as a top-down type of process for production. Generally, the top-down type of process for production essentially requires high energy because it is performed based on scission of intermolecular bond. Therefore, there are a lot of problems to be solved for production of simple periodic structure in view of multi-step processes, high cost, diffraction limit, etc.
Contrary to this, an attempt to produce a fine periodic structure by accumulating a material from the molecular level has been made. For example, as a process for production of a fine structure in 10 nm scale, phase separation of block copolymer has been known (see, Albrecht, et al., Macromolecules, 2002, Vol. 35, pages 8106-8110). Also, Francois, et al. (see, Nature, 1994, Vol. 369, page 387) has reported preparation of a structure having a regular form made of polystyrene-polyparaphenylene (PS-PPP) block copolymer. A block copolymer, which is bound covalently to terminals of polymers having different compatibilities, can vary a cycle of the phase separation structure depending on compatibility and length of each segment. However, this process also requires complicated organic synthesis process, and kinds of the block copolymers which can be synthesized are limited.
Further, a process for production of a two-dimensional or a three-dimensional periodic structure by agglomerating colloidal fine particles in submicron size (see, Gu, et al., Langmuir, Vol. 17) and a process for production of a inversed opal structure by using this as a template (see, Kalso, et al., Langmuir, 1999, Vol. 15, pages 8276-8281) have been reported, but both processes have various problems in their processes such as preparation of fine particles having a single particle size and decomposition of the template after molding.
As a process based on a different principle from these processes, a process for easily producing a honeycomb-like porous body by using water droplets as a template has been reported (JP-A-8-311231). Specifically, this is a process in which water droplets are condensed on the surface of a solution of a polymer in a non-aqueous organic solvent, then a honeycomb-like porous body is prepared by using said water droplets as a template. In addition, JP-A-2001-157574 has disclosed a process for production of a honeycomb-like porous body by casting a solution of poly-L-lactic acid in chloroform on a glass substrate followed by gently evaporating the solvent. In this connection, the term of “honeycomb-like porous body” means a thin film structured body made of a polymer, in which minute pores or dimples oriented to the vertical direction to the film are provided like a honeycomb along the plane direction of the structured body. The honeycomb-like porous body of the present invention is the same.
Patent Literature 1: JP-A-8-311231
Patent Literature 2: JP-A-2001-157574
Non-Patent Literature 1: Gerdinge, et al., IEEE Spectrum, 1989, Vol. 89, page 43.
Non-Patent Literature 2: Noda et al., Nature, 2000, Vol. 407, page 608.
Non-Patent Literature 3: Cheng, et al., Science, 1997, Vol. 276, page 1425.
Non-Patent Literature 4: Whiteside, et al., Angew. Chem. Int. Ed., 1998, Vol. 37, pages 550-575.
Non-Patent Literature 5: Albrecht, et al., Macromolecules, 2002, Vol. 35, pages 8106-8110
Non-Patent Literature 6: Francois, et al., Nature, 1994, Vol. 369, page 387.
Non-Patent Literature 7: Gu, et al., Langmuir, Vol. 17.
Non-Patent Literature 8: Kalso, et al., Langmuir, 1999, Vol. 15, pages 8276-8281.